The Quantitative Imaging/Dosimetry Core provides pharmacokinetic and radiation dosimetry information for the evaluation of therapeutic efficacy and toxicity of radioimmunoconjugates with a long-term goal of developing a computer based, comprehensive treatment program. Current work allows us to incorporate quantitative imaging methods developed by our group with the physical constants of each radionuclide to evaluate therapeutic effects and toxicity of the radioimmunoconjugate in an accurate and reproducible manner. Methodology and software has been developed that converts regional counts obtained by quantitative imaging to macroscopic tissue radiation dose estimates, and these estimates have been validated. Pharmacokinetic and dosimetry data are extracted using a single computer interface which combines serial image acquisition, quantitative dynamic image analysis and dosimetry with MIRDOSE2. Radiation doses for up to 60 radionuclides and 25 organs can be readily calculated. While substantial progress has been achieved in the development of planar and SPECT quantitative imaging methods, intensive studies will continue to be conducted on novel radionuclides (67Cu and 90Y) as well as 131I used in therapy.